Beating off competition from Joanna Lumley and Francesca Annis, Dame Thora was honoured for her role as 95-year-old Violet in Alan Bennett's monologue Waiting For The Telegram part of his second Talking Heads series.
However A Rather English Marriage beat Dame Thora's Talking Heads in the best single drama category. Tom Courtenay was named best actor for his role in the BBC drama.
It was a good night for the BBC, which also won best drama series for The Cops, best drama serial for Our Mutual Friend and best soap for EastEnders.
Chatshow veteran Michael Parkinson, who hosted the night's awards alone after the death of planned co-host Jill Dando, won the best light entertainment performance category. Since the return of his chat show to BBC1 Mr Parkinson has scored several scoops, notably an interview with singer George Michael after his arrest in Los Angeles.
The late Dermot Morgan received a posthumous honour best comedy performance for his role as Father Ted in the Channel 4 sitcom, which also won best comedy. Best light entertainment programme went to the phenomenally successful Who Wants To Be A Millionaire? which has set new ratings records for ITV. Best factual series was won by BBC1's The Human Body, which also took a special originality award.
A special award went to writer Richard Curtis, whose television work includes Mr Bean, The Thin Blue Line, Blackadder and The Vicar of Dibley. The Dennis Potter award for writers went to David Renwick, author of Jonathan Creek and One Foot In The Grave, the Richard Dimbleby award for outstanding personal contribution to factual television went to ITV newsreader Trevor McDonald, John Thaw won the Lou Grade award for his role in the ITV drama Goodnight Mister Tom, and the Academy Fellowship went to Morecambe and Wise.
